scholarly journals Two Identical Embden-Meyerhof Enzyme Systems in Normal Rat Diaphragms Differing in Cytological Location and Response to Insulin

1959 ◽  
Vol 234 (10) ◽  
pp. 2491-2496
Author(s):  
Walter N. Shaw ◽  
William C. Stadie
Keyword(s):  
Enzyme Systems ◽  
Normal Rat

FUNCTIONAL HETEROGENEITY OF THE THYROID AND POSSIBLE PRESENCE OF IODOTYROSINE-LIKE COMPOUNDS IN NORMAL SERUM

1965 ◽  
Vol 48 (2) ◽  
pp. 199-208 ◽  
Author(s):  
J. D. Wiener
Keyword(s):  
Human Subjects ◽  
Thyroid Tissue ◽  
Normal Serum ◽  
Schematic Model ◽  
Functional Heterogeneity ◽  
Rat Serum ◽  
Iodine Metabolism ◽  
Normal Rat ◽  
Isotope Equilibrium ◽  
Equilibrium Experiment

ABSTRACT After the administration of 131I to normal animals or human subjects, labelled thyroxine and triiodothyronine, but at most traces of labelled iodotyrosines can be detected in the serum. However, several investigators using various methods claim to have found considerable amounts of one or both of these iodotyrosines when assaying the stable (non-radioactive) iodinated compounds in the serum. Considering the available evidence as convincing for the present, an attempt has been made to explain this discrepancy. A schematic model of the thyroidal iodine metabolism is proposed, based on (a) the hypothesis that the iodotyrosines are present in the circulation in a »masked« form (i. e. protected against deiodination), and (b) the known functional heterogeneity of the thyroid tissue. This heterogeneity should be of a qualitative as well as quantitative nature. As the physical decay rate of 131I is short in comparison with the turnover rate of the masked iodotyrosine pool, an isotope equilibrium experiment with rats was carried out, using the long-lived isotope 125I. The results of this experiment, viewed together with those of a similar investigation published by others, seem to lend support to the proposed mechanism. The presence of non-negligible amounts of a diiodotyrosine-like compound in normal rat serum seems fairly well established.

Effects of progesterone induced postmaturity on CBG and pituitary-adrenal activities in the rat foetus

1986 ◽  
Vol 112 (3) ◽  
pp. 396-403 ◽  
Author(s):  
Jean Paul Dupouy ◽  
Alain Chatelain
Keyword(s):  
Binding Capacity ◽  
Sharp Decrease ◽  
Plasma Corticosterone ◽  
Corticosterone Concentration ◽  
Rat Pups ◽  
Body Weights ◽  
Normal Rat ◽  
Severe Jaundice ◽  
High Level ◽  
Subsequent Rise

Abstract. CBG and pituitary-adrenal activities were investigated in intact rat foetuses, in newborns spontaneously delivered by vaginal way and in postmature foetuses from mothers with delayed parturition caused by daily progesterone injection from day 20 of gestation. The postmature foetuses had lower body weights and higher adrenal weights on day 22, 23 and 24 of gestation than newborns of the same conceptional age. The corticosterone binding capacity of the plasma as well as the binding capacity of CBG for corticosterone decreased in intact foetuses for the last 3 days of gestation and stayed very low in pups from day 0 to day 8 postpartum. These parameters decreased more slowly in postmature foetuses; however, the differences between the latter and intact foetuses or newborns were not statistically significant. Similar evolution occurred in intact pregnant and suckling females as well as in females with prolonged gestation. The fall in CBG activity in normal rat pups and the subsequent rise in free steroids could explain a sharp decrease in plasma ACTH levels as well as the drop in adrenal and plasma corticosterone concentration. In foetuses with prolonged gestation, the same phenomenon did not occur. Stress conditions produced by maintaining growing foetuses in utero and the development of severe jaundice maintained high ACTH levels. In contrast, the fall in adrenal and plasma corticosterone concentrations in spite of the high level of circulating ACTH could be mainly due to the progesterone inhibition of the steroidogenic activity of the foetal adrenals.

Angiogenesis Induced by Photodynamic Therapy in Normal Rat Brain¶

2004 ◽  
Vol 79 (6) ◽  
pp. 494 ◽  
Author(s):  
Feng Jiang ◽  
Zheng Gang Zhang ◽  
Mark Katakowski ◽  
Adam M Robin ◽  
Michelle Faber ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Rat Brain ◽  
Normal Rat

Lack of islet amyloid polypeptide regulation of insulin biosynthesis or secretion in normal rat islets

Diabetes ◽  
1990 ◽  
Vol 39 (7) ◽  
pp. 871-874 ◽  
Author(s):  
S. Nagamatsu ◽  
R. J. Carroll ◽  
G. M. Grodsky ◽  
D. F. Steiner
Keyword(s):  
Islet Amyloid Polypeptide ◽  
Insulin Biosynthesis ◽  
Islet Amyloid ◽  
Rat Islets ◽  
Normal Rat

scholarly journals High Glycogen Levels in Brains of Rats with Minimal Environmental Stimuli: Implications for Metabolic Contributions of Working Astrocytes

2002 ◽  
Vol 22 (12) ◽  
pp. 1476-1489 ◽  
Author(s):  
Nancy F. Cruz ◽  
Gerald A. Dienel
Keyword(s):  
Rat Brain ◽  
Sensory Stimulation ◽  
Enzyme Inactivation ◽  
Biologically Active ◽  
Metabolic Labeling ◽  
Tissue Sampling ◽  
Normal Rat ◽  
Sampling Procedures ◽  
Very High

The concentration of glycogen, the major brain energy reserve localized mainly in astrocytes, is generally reported as about 2 or 3 μmol/g, but sometimes as high as 3.9 to 8 μmol/g, in normal rat brain. The authors found high but very different glycogen levels in two recent studies in which glycogen was determined by the routine amyloglucosidase procedure in 0.03N HCl digests either of frozen powders (4.8 to 6 μmol/g) or of ethanol-insoluble fractions (8 to 12 μmol/g). To evaluate the basis for these discrepant results, glycogen was assayed in parallel extracts of the same samples. Glycogen levels in ethanol extracts were twice those in 0.03N HCl digests, suggesting incomplete enzyme inactivation even with very careful thawing. The very high glycogen levels were biologically active and responsive to physiologic and pharmacological challenge. Glycogen levels fell after brief sensory stimulation, and metabolic labeling indicated its turnover under resting conditions. About 95% of the glycogen was degraded under in vitro ischemic conditions, and its “carbon equivalents” recovered mainly as glc, glc-P, and lactate. Resting glycogen stores were reduced by about 50% by chronic inhibition of nitric oxide synthase. Because neurotransmitters are known to stimulate glycogenolysis, stress or sensory activation due to animal handling and tissue-sampling procedures may stimulate glycogenolysis during an experiment, and glycogen lability during tissue sampling and extraction can further reduce glycogen levels. The very high glycogen levels in normal rat brain suggest an unrecognized role for astrocytic energy metabolism during brain activation.

Sign in / Sign up

Export Citation Format

Share Document